Sticky tape

Or, in this case, not.

In general, the flexible LED tapes come with a self-adhesive backing tape. You remove the backing from that, and stick the tape to whatever you want. It (apparently) works a treat. However, the LED tape suppliers also want their tape to be used in harsher environments like bathrooms, kitchens, or outside, where there may be more ambient water around. So they’ve taken to encapsulating their LED tape in silicone. This provides both protection from splashes and dampness, and also a degree of physical protection too, without compromising the flexibility or the light output.

My test purchase was of the latter type. And the problem with this stuff is that the silicone both adds weight, and is a devil to adhere to.

To resolve the first issue, the backing tape really needs to be lot stronger than that on the normal tape. In my case it’s apparently branded 3M adhesive tape, but it’s clearly only just borderline strong enough to hold the LED tape in place when it’s stuck upside down without support. The LED tape and adhesive backing tape are pulling away from the cupboard in places. But worse, in other places the LED tape is pulling away from the adhesive backing tape, leaving just that stuck to the cupboard. Silicone is difficult stuff to stick to, and clearly this 3M tape is struggling.

Now, admittedly it’s hot weather at the moment – pushing 30c in my study – but these adhesive tapes are normally rated to 100+c, so I don’t think that’s the root issue here. It’s the weight and the silicone encapsulation that are causing the problems. So, what options do I have?

When I come to do the kitchen I could switch to un-encapsulated LED tape. That would solve the problem. But it’s not going to be as easy to keep clean, and it’s going to be exposed to steam etc. That doesn’t seem like a good solution. So I really need a better approach to mounting the silicone encapsulated LED tape.

My first thought was “better adhesive tape”. There are structural adhesive tapes around (usually called Very High Bond tapes) that can even be used as alternatives to spot welding. They’re not cheap, but I hoped that they might do the job. And there are some mid-range very high strength “professional” double-sided adhesive tapes that are used to make things like advertising signs that might be OK too. So I called a specialist adhesive tape supplier, Tapes Direct, and asked for some technical help. I ended up talking to the owner, and he wasn’t convinced that any of the normal tapes on the market will work well with silicone – not even the VHB stuff at £50 a roll. Kudos to him for not trying to sell me something that wouldn’t work too – proper customer service – I’ll definitely be using him next time I need some specialist tape. But for now it sounds as though adhesive tape is not the answer.

So the other thought is to stick it in place with Silicone sealant. I suspect this is one of those situations where it will be worth paying for a good quality sealant from someone like Dow Corning or Unibond. But the problem with this is that the good quality silicones all cure slowly, developing maximum strength over about 3 days. Which isn’t going to work upside down on a kitchen cupboard.

So the solution is to get some cheap angle or channel, and mount the LED tape onto that, using the silicone, and then mount that onto the kitchen cabinet (with something like screws) once the silicone has cured. You might be able to get away with plastic channel, but my preference is for some aluminium angle; it’s more rigid, so will mount more easily, and isn’t expensive from a wholesaler, even when bought in small quantities.

So later this week I’ll demount the LED tape in my study and build it up into what amounts to a custom light fitting. The trial continues. But of course, this is going to add to the cost. By self-building, I’m currently looking at about £20 a meter for this LED lighting. Adding aluminium angle & quality silicone sealant is going to raise that, perhaps to nearer £30 a meter. It’s still cost-effective, but the differential to something like these, at about £65/m is falling.

On the positive side though, as well as being cheaper, mine are still both brighter and easier to dim!

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Let there be (dimmable) light!

I find that there is a point at which you need to switch from doing academic research to carrying out some practical experimentation. I reached that stage on Sunday evening while investigating whether LED “strip” lighting would be a good replacement for the traditional fluorescent work surface lighting.

I realised that I didn’t have any feel for how bright any of these tapes actually were, or if their characteristics would make them good or bad sources of light for work surfaces. I’d also had suggestions from contacts on Twitter that it was a lot harder to dim these strips than I was expecting.

But it transpires that in my study I happen to have a run of wall cupboards over my desk which closely mirrors a kitchen layout. The desk is much deeper, and the cupboards are mounted higher than they would be in a kitchen, but the principle is the same. If anything, my study would be a more challenging environment because of the higher mounting point and larger area to illuminate.

So I ordered 2 meters of moderately high output “dimmable” LED strip; this is built with 60 cool-white SMD 5050 LEDs per meter of tape, operating at 12v and drawing a little under 15w a meter. It’s all encapsulated in a silicone coating, and backed with a 3M self-adhesive coating. I added a 33w “TRIAC dimmable” LED driver that someone had reviewed as working successfully for them, and a Varilight V-Pro low power dimmer switch.

The advantage of that dimmer switch is that it can run with a minimum load of only 10w, unlike normal dimmer switches that usually require a minimum load of 40w or more. It’s also a “smart” dimmer switch, where the mode (leading/trailing edge dimming) and minimum brightness point can be “programmed” into the switch.

I’ve just set it all up “loose” on my desk, and it works quite well. The LED strip is very bright; more than sufficient to light a work surface under a kitchen cabinet. In fact, for my immediate “test” application in my study, it would be too bright without the dimmer.

The dimmer works very well in trailing edge mode. It’s completely silent at minimum and maximum brightness points, with only a very slight buzz from the LED driver at the mid-point. Minimum brightness is (subjectively) about 25% of the maximum, and control of the light level within those extremes is very smooth. Perhaps the only issue is that turning the LEDs on with the dimmer at anything other than full brightness seems to take a second or two for the dimmer to fire everything up. Noticeable, but not necessarily a problem.

Out of interest, I also tried the dimmer in leading edge mode; it wasn’t a good experience. The LEDs did not dim very much, and the LED driver produced a much more noticeable buzzing noise. Trailing edge is definitely the way to go, at least for this set up.

So, the summary is that the LED strip tape is fine for my intended use. I will almost certainly need to be able to dim it, and I now know that is possible without resorting to expensive professional remote-controlled low-voltage dimming, even though it’s perhaps not as ultimately good. From what I can see of the problems with this type of solution (noise, failure to start the LEDs) are probably all related to the LED drivers, so finding ones that are known to work well is going to be the key to success.

Circuit to dim 12v flexible LED strip

Update: Having had this system properly wired into my study for the last few days, a small issue has arisen; the adhesive backing tape (which I think is probably double-sided adhesive tape that is pre-applied as part of the manufacturing process) is not proving man enough for the job. About 2 days after I initially applied the strip to the bottom of the overhead cupboards, it it started to peel off. Pressing it back into place makes it stick again for a while, but it’s definitely not a good long-term solution.

At the moment I’m looking for a better fixing system, but the fact that the tape is encapsulated in silicone is not helpful, as getting anything to adhere to it is problematic. My first thoughts are around using a silicone-based adhesive/sealant to stick it up … but it will need supporting in place while everything cures, which could be interesting. More research required.

Kitchen lighting

Having had such a positive result from tinkering with my chandelier, I’ve been thinking about how I could apply LED lighting to the upcoming refit of our kitchen. Currently we are having LED down-lighters in the ceiling, tri-phosphor fluorescent lighting over the worktops, and standard 40w incandescent candle bulbs in the extractor hood.

I think that the main LED down-lighters will be fine, subject to getting the right colour temperature, and having a way to dim them. But I’m now much less happy with the idea of tri-phosphor fluorescent worktop lighting, and the incandescent lights in the extractor hood. I’d now like to go LED everywhere in the kitchen, if only to colour-match the lighting.

The extractor hood is slightly frustrating. All the different hoods are basically just a metal enclosure, some filtration, some fans, and some lights. The pricing for that varies wildly, and without much obvious logic to it. We wanted as large an extraction rate as possible, in a simple chimney style hood, with LED lighting. To get LED lighting we would have had to get a much lower rate of extraction, and pay a huge amount more, so in the end we decided the extraction rate was more important, and got the one with incandescent bulbs.

However, a bit of poking around in the showroom reveals that these bulbs fit into a pair of back to back SES/E14 sockets, and shine down through perspex lenses. So I’m already thinking that I could convert that to LED before it’s fitted. Another of those little 12w LED drivers from Amazon, a couple of these G4 “panel” type bulbs, and pair of these neat little converters from ATEN Lighting (so I can use the existing SES sockets as mounting points) should see me good.

The worktop lighting is somewhat less clear. There are (hideously expensive) pre-made LED lights designed to fit under cupboards, and be daisy-chained together much like the old T5 fluorescent fittings. I guess that’s convenient for the electricians, but at anywhere from £50 to over a £100 a meter (depending on what you buy, and where from!) that’s never going to fly from a budget perspective. On the other hand, you can now buy flexible strips of splash-proof LED’s that come with a self-adhesive backing on them for around £40 for 5m. Simply add a driver and you should be good to go.

Of course, it’s not quite that simple. There are a lot of different makers of strip LED, with different LED types, densities, etc. And what kind of driver do you need? And actually, I’m going to end up with several runs of this stuff, each on it’s own driver. How to do I connect them all together? Worse, in an ideal world I want to be able to independently dim the ceiling down-lighters and worktop lighting. Suddenly this is starting to look more complex. No wonder the kitchen fitter wanted to use fluorescent tubes!

Still, at the moment it looks like I need:

  1. A dual gang, low-wattage, trailing-edge mains voltage dimmer
  2. The down-lighters wired in parallel directly to the dimmer
  3. The various worktop strips to be dimmable, and also wired to dimmable constant current LED drivers
  4. Those drivers then wired in parallel to the other channel of the dimmer

With a bit of thought it may even be possible to add some interesting “accent” lighting, as additional circuits in parallel with the down-lights. But at this point I need to do more research, and talk to people who’ve done this. So if anyone has any insight to add, please leave a comment!

Converting halogen chandelier to LED

About a decade back we bought a modern chandelier, powered by five 20w G4 halogen capsules. It’s a really lovely feature light, covering the hall, stairs and landing. Unfortunately, in the intervening time, electricity costs have rocketed, and we’ve all moved to lower-powered lighting using things like compact florescent lamps (CFLs) which cost a fifth of what old incandescent bulbs did to run. That chandelier is now the only incandescent fitting left in our house, and by far the most power hungry to run.

As a result we’re careful to turn it off whenever we don’t actually need it. As this defeats the whole point of having a feature light like a chandelier, I’ve been trying for some time to find a way to reduce it’s power consumption.

Newer technology halogen capsules were the first choice; the original 20w bulbs got switched out for 15w equivalents, that produced approximately the same light. But boy were they expensive, and they lasted 1000 hours at best – a year or so. So I’ve still been looking for alternatives; CFL was never going to work aesthetically, but LEDs seemed to hold promise … though the light output of early LEDs was not great, and no-one supported the G4 form factor anyway.

But recently I noticed manufactures were trying again. Mostly they were building simple circuit boards with a few high power SMD LEDs on each side. I don’t doubt that they work, but I suspect the beam angles would make the field of light very patchy. They look awful too!

And then I noticed these: 24 SMD LEDs mounted onto a neat cross-shaped circuit board. Nominally 360 degree beam angles, with the whole thing encapsulated in some type of silicon for physical robustness. Finally, something worth the gamble.

G4 Halogen capsule and G4 LED alternative

The existing 12v halogen transformer is apparently not suitable for driving LEDs so I picked up a cheap 12W LED driver from Amazon to replace it. In total, a little over £20 for 5 LED G4 replacements, the LED driver and the P&P.

LED driver and G4 LED bulb with halogen G4 bulb and AA battery for comparison of size

And the result is pretty good. The LEDs are extremely bright, and look simply wonderful in the chandelier. However the nature of LEDs is that they are extremely directional, producing a tight beam of light. When you’re in alignment with the output beam the LEDs are extremely bright. However, off-beam they are much less bright that an incandescent bulb that acts more like a point light source, radiating in every direction. The fact that there are 120 little surface mounted LEDs each pointing in slightly different directions helps enormously, but the overall room illumination from the chandelier still just isn’t as bright as it was with the old halogens.

It is, however, more than bright enough, and is only using 6w 7.5w rather than 100w to run, so we can run it as much as we like now. That’s a pretty good compromise in my book!

Update: I was asked for a picture of the end result. So here it is, taken at night, with the chandelier lit up, which makes the picture look a lot darker that it is in real life. The walls are also a light purple colour, accentuating the cold blue-white colour of the LED’s:
Picture of the lit chandelier

Medical costs

One of the things that we all are exposed to is the ever rising cost of medical treatments. Whether that’s through the NHS, which we all fund through taxation here in the UK, or private health insurance, funded either privately or by nature of our employment, the escalation in the cost of providing care to us hits us all in the pocket eventually.

This has been brought home to me by observing the disposable culture in the hospital I’m currently staying in. The amount of stuff that gets used once and thrown away, rather than reused (or recycled) is amazing.

Now, to be fair I do understand that when dealing with body fluids, especially ones that are potentially infected with unpleasant diseases, the normal routes for reuse and recycling may well be closed off. And there are a large number of situations where the safety of the patient is going to come before concerns about the environment or the cost. But at the same time, I can also see that there is a huge opportunity for reuse too.

I guess what crystallised this for me was an accident that I had with my endsponge drainage system today. I was sitting on the bed, and went to stand up, only to discover that I was standing on the catheter that runs from the sponges to the vacuum flask. The primary result was that the catheter was pulled loose from the sponges at a conveniently (and probably carefully) situated “Y” join, preventing the endosponges being dragged from my body. For which I am eternally grateful. But the secondary result was that the vacuum flask immediately devacuumed, leaving me with no way to run the endosponges.

In the end it took 2 hours to get a replacement unit from the operating theatres to replace it. We got several *other* vacuum drainage flasks before that. But none of them were compatible with the Endosponges. And the devacuumed flask is not refillable, despite there being plumbed-in vacuum lines in every room in the hospital.

Worse, they don’t even appear to be recycleable, despite appearing to be made from extremely sturdy polycarbonate, which ought to easily withstand being medically autoclaved.

As an outsider looking in, I do wonder just how much money could be saved by standardising on a small selection of vacuum flasks covering a range of pressures, with standard fittings that can be attached to anything that needs a vacuum source to operate, that can be topped up from the hospital vacuum system whilst in use, and that can eventually be emptied and medically autoclaved, before being locally evacuated with fresh vacuum locally, at least some minimal number of times before eventual complete disposal.

My treatment will eat through at least 20-odd of these flasks; even halving the cost of that (I’m assuming that as with all medical devices, these things won’t be cheap!) starts to look quite attractive.

Green printing?

This week my trusty old Canon IP4000 inkjet stopped working. Changing the cartridges and running deep cleaning cycles make no difference. The print quality has been slowly falling off for some time now, so my suspicion was that the print head had finally died. I suspect the printer must be something like four or five years old now, so it’s not perhaps not unexpected.

What was unexpected was the cost of a replacement print head; the cheapest I could find was nearly £70. Add in another set of cartridges at £30, and it becomes significantly less expensive to just buy the new replacement model printer from Canon (the IP4850) at about £75 delivered. Which is just completely ridiculous.

In addition I’ve always been frustrated that the inkjet cartridges always seem to run out at an alarming rate. The manufacturers quote the capacity in pages of 5% coverage (340 pages, apparently), which may be representative of average business use, but decidedly unrealistic when you have three children printing lots of full-colour diagrams as part of their homework. I doubt that I got more than a hundred pages before one or another of the colour cartridges started running dry. Keeping the printer supplied involved the frequent advance purchase & stockpiling of cartridges.

Of course, printing technology has moved on in the intervening years, so I decided to do a proper examination of the options available against my expected printing requirements over the next few years. This is heavily influenced by the needs of my daughters who are entering the stage where they will be doing a lot more homework as part of their GCSE and A levels, and my need to produce the occasional “customer ready” document at home.

My requirements; Linux support, excellent black and white performance, automatic duplex (saves so much paper!), the ability to print colour diagrams, and a volume of approximately 200 pages per month. Long term cost of ownership is more of a factor than the purchase price, and we have no requirement for photographic printing, as we print photographs via a bureau.

To my surprise, the latest generation of SOHO colour laser printers compete very favourably with inkjets on total cost of ownership. There is no doubt that they are still more expensive, but to compensate for that, you get better print quality, faster throughput, and the convenience of much longer between (more expensive) toner cartridge changes.

In the end I narrowed the choice down to either the Canon IP4850 inkjet, or a Lexmark C543dn laser printer. Both had excellent reviews and represented the best fit for my expected needs for their respective technologies. However, finding a supplier offering the Lexmark with a 50% discount pretty much decided the issue; £150 delivered, with full capacity toner cartridges installed is hard to beat.

I took my old Canon IP4000 down to the recycling centre yesterday. It felt really wrong to be “throwing away” something that with a little maintenance is basically capable of continuing to provide good service. But economically it just didn’t make sense. I felt very un-green.

Meanwhile the Lexmark is installed on my home network and working beautifully. I spent some time fiddling with the printer settings to reduce the toner intensity levels and the timeout period before the printer drops into its lowest power-saving mode, both of which ought to help me save money. It does mean a twenty second delay before the first page is printed while the printer warms back up, but once running it churns out paper at 20 pages a minute, so overall it’s a lot faster than the old inkjet we were used to.

Energy usage

I’ve been tracking my homes annual energy usage for several years now. For the last few it’s been fairly stable at around 19,000Kwh gas and 6,500Kwh electricity.

This year, with our new central heating boiler and maximised loft insulation, the figures are 15,500Kwh gas and 5,800Kwh electricity.

Taken together this reduces the carbon footprint of our home from 7.05 to 6.02 tonnes. The drop in gas usage is responsible for most of that, and is very welcome indeed. The electricity drop is good news too, though apart from forever going around turning lights off after my kids, I can’t account for any real changes in our usage, which is odd. However, I suspect it could be easily accounted for by something as small as using the oven a little less each week.

Now, if only I could find some reliable figures for the UK average to benchmark myself against…